In the U.S. armed forces and those of many other countries tactical voice communications currently are carried out with VHF (Very High Frequency) FM radios which do not include any provision for anti-jam protection, privacy, prevention from intercept or frequency management. The technology of electronic warfare is rapidly advancing and the possibility that a hostile party will utilize active jamming and passive intercept is becoming more likely. It is clear that tactical radio communications must be adapted to cope with developing electronic warfare threats.
A great number of tactical radios are now in the inventories of the military services of the United States and other countries. It is not practical to phase out the existing radios and totally replace them with advanced radio systems having anti-jam and privacy protection features. Further, such a total replacement of existing radios would be prohibitively expensive.
An effective approach for reducing electronic warfare threats, and one which is compatible with the design of many existing radios, is to change the radio frequency operating channels on the most rapid basis possible. This reduces the probability that the communication channel being used will be either jammed or subject to intercept. The current practice is to plan frequency allocation in advance then print and distribute the radio frequency assignments for upcoming time periods. However, this type of system generally has a frequency change only on a daily, or less frequent basis. This provides little protection from intercept or jamming. But merely increasing the rate of frequency changes using the preplanning technique would generally not be effective because more frequent channel changes would consume excessive operator time and the distribution and control of the printed matter describing the allocated frequency channels would be a cumbersome process subject to security breaches.
Therefore, there exists a need for an apparatus and method to operate conventional tactical radios in such a manner as to provide changes in frequency channels at a rate to reduce the probability of jamming or intercept while at the same time eliminating the operator burden of radio tuning and the problem of distributing frequency channel schedules.